Incidence of splenic malignancy and hemangiosarcoma in dogs undergoing splenectomy surgery at a surgical specialty clinic: 182 cases (2017–2021)

The objectives of this study were to evaluate the risk and predictive factors of splenic malignancy and hemangiosarcoma in dogs undergoing splenectomy at a surgical specialty clinic. Medical records, hematologic results, surgical reports, and histopathologic results from 182 dogs that underwent splenectomy for the treatment of splenic masses or nodules were reviewed retrospectively. The majority of dogs (57.7%) had benign splenic diagnoses with no malignancy. Hemangiosarcoma was diagnosed in 32.4% of the dogs. A final multivariable model indicated that thrombocytopenia, anemia, and a smaller diameter of the largest splenic nodule were risk factors for hemangiosarcoma (P<0.001), and hemoperitoneum (P = 0.01) was an additional risk factor when nodule diameter was not evaluated. There were 91 dogs that had hemoperitoneum, and 60.4% of those dogs had malignant splenic lesions. Of the 33 dogs that underwent a splenectomy for incidentally identified splenic lesions, 93.9% had benign splenic lesions. Breed size was not a significant predictor of splenic malignancy risk; however, all 6 of the German shepherds included in the study had a hemangiosarcoma diagnosis. Overall prevalence of splenic malignancy including HSA may be overestimated in some canine populations.